Rolling shelf



F. J. POWELL Aug; 1, 1933.

ROLLING SHELF Filed May 9, 1932 3 Sheets-Sheet l NN@ l EN F. J. POWELL ROLLING vSHELF Aug. 1, 1933.

Filed May 9, 1932 3 Sheets-Sheet 2 Nw www Aug. 1, 1933. F. J. POWELL 1,920,666

` ROLLING SHELF Filed May 9, 1932 3 Sheets-Sheet 5 zo gi/4j i )fijas j Patented Aug. l, 1933 j 7 'w w w 1,920,666 l l ROLLING simili1 'l s Floyd- J. Powell, Marshall,"Mo., assignor toxUllinI i l A. Burnett, Marshall, Mo.

Application May 9, 1932.*seria1` No. 610,291`

` 8 Claims. (Cl.l 214-765) w Thisinvention relatesytorolling shelves, and .and adjacent 'cooperating portions-'ofthe mecha# Y, A more particularly to'a shelf :or rack having a nismforiv supporting andadjusting the movable movable platform for supporting articles thereplatform; f n y on, the principal object of the inventicnbeing to Fig. 9 is ya fragmentary View,l on an enlarged provide and adapt such a device for use on trucks Scale, and in Vrl 56051011, akn SllvbSaIltally and otherv vehicles for the'transpor'tation and on the line 9 9 of Fig. 8; rand y 69 delivery of various articles and commodities, but i Fig. 10 is a detail sectional` viewillustrating i. l y

without limitation to said particular application the preferred practical means for attaching the and use. Among other objects to be attained `l'IlSVelSe article 'Supporting ISlabs alnd'alt'cl is to produce a structure which is `simple and 1311511611 'element 0f ll'fhfiIIIOVfLle Platform t0 H1665 10 easily operated, yet durable and possessing the endless belt members. i L r requisite load sustaining qualities and at the Referring 110W t0 the-drawngsihegnumeral15' f` same time being inherently yieldabie to a iimii'ed designates-aana of longitudinal Side frame mm# extent in `order to compensate for the ordinary vbers which, as shown, are in cross-sectional` form torsions and strains to which the body 4of' a 0f ordinary commercial channel beams with their 70 vehicle is subjected in use. Further objects and flange DOIODS l'diSpOSed inwardly: These side advantages of the invention will hereinafter frame members 15 are Connected atntervalsinmore fully appear. i i termediate their ends by cross frame members 17 ,The inventionl consists iin the novel general which are integrally Welded orotherwise'Secured-v structural arrangement and adaptation, andin at their ends to said sidefframe members;` Said 7p 20 the severalparts and combinations and arrangecross frame members llmayb Of any dsirable ments of parts as hereinafter described and crosssection, but, as shown, they are in the forrn pointed out with particularity in the appended# of plain flat bars. The endfportions ofthe two y claims. i I side frame] members 15 are connected-v by cross v 1 In the accompanying drawings, forming'part members vlVl/llih, aS ShOWI'lQaIe Preferably in 8'0 of this specification, and illustrating a practical the form` of channelswith .their ange DOI'OIIS adaptation of the invention, 19 disposed inwardly ofitheframe.

Fig. 1 is a top plan View of the rack or shelf In the structure'shown the rack or' shelf frame frame'with the .movable platform and operating comprising the` parts justy above noted furthery parts assembled thereon, the movable platform Vincludevs upstanding side frames, or platesthere 85 1 being adjusted with its article pusher element in being two practical arrangements illustrated. In

rearmost position; f theonefpreferred structure as illustrated in Figs. Fig. 2 is a similar view, with the movable 1 to 5, inclusiva'of the drawings, the upstanding `platform operated and the article pusher eleside frames comprise,vertical supportsZO which ment in forwardfposition, and parts of the` struc-4 arewelded or otherwise secured tothe' outer faces ture being broken away to disclose detailsof of the lower side frame members 15, andlsecurled other parts otherwise hidden from View; on the inner `sides; of saidyverticalsupportso Fig. 3is a longitudinal section, taken substanare longitudinal `rails 2l. Inthis connection,.it tially on the line 3-3 of` Fig. 1; may be here stated that .,the several parts de-` Fig. 4is a longitudinal section, taken substanlscribed, up to and` including `the supports 20, 95 40 tially on the line 4-4 of Fig.l2; f l f 1are preferably constructed" of. metal, While said Fig. 5 is a view,- on an yenlarged scale, and rails 2l are preferably woodeinfalthoughthey` illustrated as `a cross-section, taken` substanvmay be obviouslvmade ofmetal or any other` tially on the line `5 5 of Figs. l and3; 1 suitable materialsuchascompressed fiber orthe Fig. 6 is a cross-section, on an enlarged scale, like. Avr modification of the upper `sidefranie 100 .taken substantially on the -line 6 6 of Figs.. l portions of the structure is illustratedin. Figs. 6Y

and 3, but showing the modication of the strueand 7 of the drawings, wherein vertical supports ture of the article pusher elementof the movable 20a, similar to the yhereinbeforementioned sup# platform and also ofcertain parts of the rack ports 20, are provided,` but, in lieuof'tthe hori-` v or shelf frame; f z ontal rail members 21,*p1`ates'21EL are substituted, 105 Fig. 7 is a fragmentary View, in longitudinal `and said plates, as shown, being, ofiajthickness section, taken substantially on `the line '1 7 of obviously lesstlianthe thickness ofthe respec-y Fig. 6; i l tive rail members 21,inasmu'chas the Aplates are i Fig. 8 is a fragmentary partial plan view and ofa Width-dimension substantially equalftofthe horizontal section', on an enlarged scale, of the overall length of the portion of the respective 110 oppositefend portions of the rack or shelf frame .vertical dsupports 20%abov`e the lowers'ide frame l members 15, it, of course, being understood that said members 21 and 2.1a are'fastened securely by rivets, bolts, orother approvedl means to said `vertical supports 20 and 202, respectively.r

Secured on top of the lower side frame members 15 andA to said vertical supporting members 20 or 20a, as the case may be, are longitudinal angle members 22, said members serving as guideways for the movable shelf or platform and cooperating article pusher element, to be now described.` Generally stated, the movable shelf or platform is constructed so as to be iiexible and A s vflange portions of said members 22, and after leaving said supporting and guiding members 22,

" in the operation of the device, riding on thelower horizontal inwardly disposed flange portions 16 n of said lowerside frame members 15,said transverse bars or slats 23 being secured to .endless belts or operating elements 24.

'L In the illustrative structure disclosed in the drawings, the elements 24 are endless belts of the ordinary commercial `canvas belting or webbing, leather, or other suitable materiaLand, as shown more 'clearly in Fig. k10 of the drawings, the 'transversebars' or slatse23 of the movable platform, and the bottom"members` of thev article l' pusher element, to be presently described, are fas- I prises a cylindrical lopen-ended tube 30, on the A tenedvto said belts 24,'preferably by means of rivets 25 of .the'two-piece type, or, in otherwords, fastenersv ofthe character comprising a'head'ed stud member 26 which is axially boredl'and screwthreaded to receive a headed screw member 27, by which provision saidshelf or platform parts maybe readily detached from the belts `24 and replaced. at wi11.

The endless belts 24 maybe prcvidedin any necessary or desirable number,` but, obviously, for maintaining the proper correlation of the transverse bars or slats 2 3 in the operation of the movable platform, at least `two `of the belts are required, it being understood that additional belts 'may be desirable, dependingupon the dimensions body frame of the shelf or rackrespectively adjacent the forward and rear end vportions of the v"frame, said rollers being relatively adjustable in opposed relation to each other and under spring tension tending tovmove one of the rollers awayv from the oppositeroller at` all times, whereby to.

y.maintain ther belts in a tautene'd' condition.

Preferably,'the rear roller 29 is the adjustable one. As shown, each of the rollers 28 and 29 ccminside of; which, near veach end, is provided a fixed collar'31 to aiford an annular shoulder against which an. inserted antifriction bearing 32 abuts. Inths connectiomit may be here noted f that the shoulder-may be provided by means other Y Athan said collar 31, that is, by annularly crimping the tubef30 or otherwise forming lthe shoulder integrally therein, and the antifriction bearing may be of any desirable type.v As shown, however,

more clearly in Fig. 9 ofthe drawings, said antifriction bearing comprises an annular outer member k33 having inturned marginal iianges for the retention therein of an outer bearing ring 3 4 and an inner bearing ring 35 between which a series of balls 36 are interposed, it being understood that the outer body ring 33 is, fitted tightly within the roller tube 30, and the outcr'bearing ring 34 within said outerbody ring 33 is freely rotatable with respect to they inner bearing ringl Extending axially through the roller tube.30 is a spindle rod or shaft 37 whose'opposite'end portions are projected through and beyondthev inner bearing rings 35, one end portion of saidj spindle rod or shaft 37 being serewthreaded, the opposite unthreaded end portion being inserted with a loose fit, as at 38, ina bore provided therefor in the stem portion of a T member 39, the head portion of said T memberyhaving a plain longitudinalfbore through which an adjusting screw viofextends with a loose longitudinally slidable fit.` The screw 40 is threaded throughout nearly its entire length, and on said threaded portion an adjusting and abutment nut 4l works, and cooperating with said nutll is a lock nut 42 by which said nut 41 is fastened-in its adjustedposition. Thescrew-threaded opposits end portion 43'of thespindle rod or shaft 3'? is inserted in' a counterpart threaded bore in 47,- with whicl'i cooperates a lock nut 48' in a mani `ner similar to the hereinbefore mentioned nuts In assembling lthe part-sjust above described, the T members 39 and 45 are screwed onto the ends of the spindle rod or shaft 37 until the axes of the bores in the head portions of said T'membe'rs coincide with the planes of the axes screwv members are placed in position. this is accomplished the curved recessed end portion of the spindle rod or shaft 37 is in close proximity to the'periphery of the screwA 46,'but without binding Contact therewith, in whichre-v lation. the T member 45 is 'fre'eto move longitudinally of the screw 46, but said spindle rod or shaft 37 is held from rotation.

-of said screw members 4U and 46 when said When` By the construction and relativearrangement of the parts of the roller 29 and its cooperative connections with the screw members 40Vr and 46,

the roller isreadily adjusted'longitudinally on said screw members to tau'ten or loosen the endless belts 24, as the case may be, and according to the direction of movement in effecting the adjustment. So,- too,` while the construction Sand arrangement is effective for maintaining the end less beltsy 241m pr'opei'lworking condition, there is a certain amount of looseness in'l the'engagement of certain parts of the structure which provides for limited vyieldability to compensate for to be warped or distorted to the extent of interfering with the free rotation of the roller 29. f

v bar orslat 23.

As shown, the front roller 28 comprises acylin-r drical open-endedtube 49, identical with the tube 30 constituting the' rear roller 29. Within the tube 49 are the'annular abutment rings or shoul` der members 50 and antifriction bearings 51,`A

identical with the'corresponding parts 31 and `32 inv the rear roller tube 30. The front roller 26 is mounted on la spindle rod or shaft 52, simi"-` lar to the rod or shaft 370i said roller 29,; one

`end portion 53 of said rod or shaft 52 being screwthreaded and fitted tightly into .a correspond"-r ingly threaded borein an elbow member 54, the

opposite end portion 55 `of said rod or shaft52; -being preferably without screwthreadsv and inserted with a somewhat loose fit into a bore in anelbow member 56. By this arrangement the spindle rod or' shaft 52 is normally held from rotation Within the one elbow member 54, under normal conditions and operation of the mov-` able article supporting platform or carrier of the shelf, but' there is permitted limited relativemovement between the shaft and the` opposite elbow Vmember -tocompensate ,for the effect of lim-` ited strains and -torsions on the general frame: structure.

i Each of the elbow members 5,4 and 56has; the

screw-threaded end portion 57 of a tension bar` or rod 58 secured tightly therein. The two rods 58 are arranged in parallel relation to each other;

and respectively located adjacent to `the, lower sideframe members 15, said rods being'mounted inapertures provided therefor in the pair of adjacent cross frame members 17 so as `to' be freely slidable longitudinally. i

Working on the screw-threaded portions of` the rods 58 are tensionadjusting and abutment 4nuts 59 which are held in their respective adjusted positions by lock nuts 60. Coiled aboutthe rods 58 and interposed between said adjusting and'nabutment nuts 59 and one of thecross frame members 17, are springs 6l which areconstantly exerting a force tendingto'inove thev rods 58 forwardly and thereby create a tensionv on the endless belts 24, said springs, obviously automaticallytautening the belts should they stretch, or said springs will automatically yieldy to peri mit shrinkage of the belts, as either of said effects occurs due to weather conditions orkusage of the device. 4

In order to reinforce the body frame of the structure and to `afford a support for the trans-` ing an upright abutment frame or plate 65 which engages the rearmost article or articles lon the carrier or platforrnand `insures `the movement` of the` articles as thecarrier or platform lisr movedv forwardly.- As shown in Figs. 1 to 5, inelusive, the abutment 65 is an open frame comi.

prising transverse bars 66` in lsubstantially the same plane withthe longitudinal bars 2l of the upper side frame structure, and being 'of' such length that their ends just clear said sideframe 66are secured on 4the Ifront faces of,` the upright legs 67 of L`shapedfbracket memberswhose horizontal legs 68 are extendedv forwardly and have secured on their undersides a series of j transverse bars or slats 69 in 'spaced parallel pusher element. Preferably, the" bars or slats bars orv rails 21; f These vabutment bars orrrails Vrelation and 4.corresponding in dimensions to the `transverse bars or slats 23 of thefmovable carrier or platform, hereinbefore described, said bars 69 constituting a slatted bottom for the article ,s

66 and `69 are fastened tothe angle bracket members 67 and 68' by meansof rivets 70, of the same typer as lthe hereinbefore describedirivets 25', by which ,the transverse bars orslats 23` are fastened tothe .endlessl belts 24.` vIn this` connection it .may be ,here stated lthat thefforemost bottom bar or barsk 69 of the articlepusher element havethe saidy endless belts 24 fastened to the under sides thereof so that, Vwhen the bars i or slats 23 of the article carrier` or supporting platformymove `forwardly or rearwardly,r asthe case may be, said article pusher element moves i in the same `direction therewith. In Figsiu and r7 the vabutment member of Athe article pusher element 65 lcomprises a plate 66e which is riveted or otherwise secured 'to the upstandin'g leg portions 67 ,of the bracket members, as inthe structure of the article pusher element just previ? 'ously describedfand .the bottom of the modiiied kelement vcomprising a` plate 69L inflieu of the hereinbefore mentioned bars or slats 69, said plate being secured to the forwardly extending horizontallegs `68yof `the, bracket members, ,and i the endlessbelts 124 beingsecured to the under Aside of said bottom plate 69a, as best shown in Fig. 7v 'of the drawings.`

' For convenience and facility in operating `the movable article'carrier orI platformof the device,4 an endless belt 71 is `preferably provided,

substantially as shown. However, in some cases, E. i the endless belt 71 may be omitted andthe ymovable article carrier or platform moved forwardf` ly andrearwardly by the operator grasping .zthe `transverse bars or slats` 23` which -are` Within reach, or, `'in other cases, other actuating means-'-` may be substituted for theendless operating beltv` 7l, which latter is obviouslyvery simple in its application and use` and has'been`- found to be very practical in most adaptations of the invention. 'As shown,` the endless belt ,71 is fastened to the under sides of the forward'ibottom bars 69, or to the under side of the bottomv plate 69%, 4

asv the case may be of the article pusher element 65, thebelt 71 :being passed over the rear roller` 29 and ,also` about the lforward roller 28,A

with .considerable slack Vso that a vbight 'orropenv loop of considerable dimension isaiorded at thek front end of the shelf for the convenient grasping and manipulation of the belt in moving the movablearticle carrier or platformand the con-f. nected cooperatingarticle pusher element at the 1 rear thereof.v

In order tovpermit theendless beltse24which,

f of course, are maintained Vin tautened condition about the opposedrollers28 and 29, andthe trans` i verse barsor slats 23 on said belts to Amakethe,`

turn-around the forward roller 28, in the ioperation of the device, said operating belt 71vis carried up between theforemost bar 69, or the front. edge of the plate 69a, as the case may be,` of saidA article pusher element 65, and the rearmost bar' i `or Slat.v 23` of saidjmovable article carrier or platform, and thence vcarried forwardly over all of lthe bars or slats 23 which are riding on the'longiand articles or commodities are placed on .l Vthe device the movable carrier or lplatform is intermittently moved rearwardly 'by lthe operatorv kpulling on the lower flieht of the endless belt 71,

and .continuing the operation until the article pusher. element 55 reaches its rearmost position.

VObviouslyto unload the device the operation :is

reversed. `lit is, of course;y understood that the front end of the kbody frame is open throughout the entire Width thereofeizcept for the hereinbefore-'desc channeled cross frame 18, and possibly ay supplemental cross frame member leyas shown more clearly in. Figs. 3 and '4 ofthe drawings.y f However, at the rear end of the body traine, the i crab-ly: connected by a cross bar` 2lb which serves lnot only to brace the upper side frame'menibers,

r side members are preibut aords a limiting-stop for arresting the rear- Ward movement of the article pusher element 55. `In practice, the invention maybe incorporated .in a builtin'structure in the forin oi a rack; or

shelf, or it be obviously incorporated in portable structurein the forro of indoor or floor trucks,v aswell as regular: outdoor service andl delivery truck". t is thelast noted use for which the invention is primarily intended, and for which the structure has leen. more .particularly designed in order to take care of the various strains and torsionsto'whichthe bodies of the trucks and the contained racks or shelves are incidentally `subjected, in use.

In the adaptations of the invention the body vfran/ies on whichthe movable v.article carrier or supporting platform is mounted may be iixedly located, but in niostcases the supporting frames .will bereinovable, to` this end it is preferalile [to provide the body fi `ne Wi antiiriction devices of sonic suitable type.

rollers or other shown in the drawings, v.the body frame :is provided with `clis'c-lil;e rollers 'l2 which are located on the outside of the lower longitudinal frame shouldered studs 273, which are insertedv through apertures provided therefor in the side-frame members l5 and securedl in place by nuts 74. By

I this provision the racks or shelves may be readily placed upon and removed from-supporting track:m

ways provided. therefor inthe service or delivery truck or `the like. .l f y* The device ofthe present invention facilitates the handling` of articles and cominod variu 'ous kinds, partlciilarly bakery goods and the gen-- eral line offood products and other commercial.m

ized commodities, as the movable carrier or platform is readily loaded and unloaded from one endvr thusV obi/latins the necessity for the user" reaching at great len t1' 'n placing and removing articles or nece ating his entering the truck ormoving from his posi on therese ug and delivering: end. oi the device, which is the same.

As shown in the drawings, the device may be provided with abrush. 'Z5 extending` transversely .of the 4forward endy portion of the body frame,

thei brush being conveniently `mounted. Within oney by with the other,

' ther.'

one and the channeledend frame member 18, :andthe bristles projected inwardly ofthe device adistance sufficient to engage the bars or slats 23 as pass around the front roller 28. .This provision is of material advantage in keeping the movable platform oars or slats 23 in a clean and sanitary condition, and, obviously, theiocatio of Athe brush element-,75 maybe changed as cumstances may dictate. v it inay be here noted that the forward end porl and scope ofthe invention. For exan'iple, sprocket chains and `gears lmay be substituted for: the endless belts ,24 andfrollersv 28 and 29 as shown, and various ystructur-ilmaterials substitutcdor used'in combination in' Ythe different Barts of the device. s not limited to the precise construction and. ar-

tr shown in aterials f i, v

Having thus rdescribed my invention, whatl claim as new and'desire to, secure 'by Letters Patentis: .n 'y .l f.

l. Tn arolling shelf unit, a Vrectangular body endless belt means on saidbody'fraine, a .movable platform element 4comprising trans verse slatineiubers respectively secured to 'said endless belt*meansV vl" ebyto be movable the w w a framev for slidably supporting the opposite end portions ofaid platform slat members movably 'n separatelyI from said endlessY belt means, and@I palate endless belt means connected to said pla' "o yelement' for moving said platform clero nt 'said'nrstinentioned endless belt ineansv f their. connectd relation. 1 l i 2. Ifo-a rolling shelf unit, a rectangular body frame, endless beit means on said bodyfraine, a oldable platform element secured tofsaid endless belt means whereby to movelongitudinally therewith, a separate pusher elernentlocated at the rear of and having a complementary platform portion cooperatinef vvitli'said foldable platform element, said pusher eleinentbeing connected to said endless belt means whereby to bewinovable cooperatively rwith `said means'and platform ele nient, means on said body ytraine forslidably supporting and guiding said movable. platform element and said pusher element separately from saidA endless belt rneans'inv their movement. with said endless belt ineens, and-separate endless belt ineans connected to said platforinand pusher elements for manually operating them.v simultaneously. v

3, A portable rolling shelf of the character de# scribed,.comprising a rectangular body frame,

transverse antifriction roller supporting means on body frame, normally tautenedfondless on said antifriction roller supporting operatiey longitudinally ofbody frande; a i "ld le platforrn'-keleinent @movable longitudinally o1 said body frame and being oonnected. to said en ss beit means whereby'to `be Iinoved the one by and with the other, meanson said body frame for supporting said foldable platform element slidably thereonwindependently 'of The invention, therefore,v

neans vron said body the drawings, nor f inthe f said endless belt, means, and separate endless belt Ineans, in normally` loosened and extensible condition, for manually operating said iirst men- `tioned endless belt means and said connected foldable platform element.

4. The herein described rolling shelf structure,

" comprising a rectangular body frameja pair of" transverse rollers supported in opposed relation Vto each other on said body frame, one of said rollers being adjustably supported at its ends on longitudinal frame members, the other roller being mounted on longitudinally movable frame.-

members having cooperating spring tension elelments actingk normally to move saidvlast vmentioned roller in the direction awayfrom said adjustably supported roller, leachv of said rollers comprising a tubular outer member provided at its opposite end portions with internal antifric- `tion bearings, a spindle rod extending `axially,

through said antifriction bearings,l and lcoupling members for supporting said spindle rods `on said longitudinal roller supporting frame members aforesaid, one end portion of each of said spindle rods beingv rigidly secured to its said coupling member, and the opposite end of the rodbeing capable. of longitudinal and rotative movement with relation `to its coupling member. v

5. The herein described rolling shelf structure,v comprising a rectangular body frame, said `frame including channeled longitudinal side members With their flanges disposed inwardly, cross frame members connecting said side framemembers, vertically hanged longitudinal guidewayson top *of said channeled side frame members, a foldable platform comprising transverse slat members movably supported at their endsnormally on said flanged guideways, said lplatform slat members inthe movement andfolding of said platform being movable to and slidably Asupported on the lower flanges of said channeled side frame members, a separate pusher element having a horizontal article supporting base portion slidably supported on said longitudinal vertically hanged guideways cooperatively atfthe rear of said foldable platform, normally tautened endless beltv means on saidframe connected to the respective slat members of `said platform and l to said pusher element, whereby said slat members and said pusher element are operablethe one by and with the other and an additional endless belt, in normally loosened and extensible condition, for manually actuating said platform and said pusher element in either direction, forwardly or rearwardly. l

6. The herein described rolling'shelf structure,

comprising a rectangular body frame, said frameV including channeled longitudinal` side members with their flanges disposed inwardly, cross frame members connecting said side frame members, vertically flanged longitudinal guideways on top of said channeled side frame members, a foldable platform comprising transverse slat members movably supported at their ends normally on said flanged guideways, said platform slat members in the movement and folding of said platform being movable `to and slidably supported on` the lower anges of saidchanneled side frame members, a separate pusher element having a horizontal articlesupporting base portion slidably supported on said longitudinal vercured to the under sides of said transverse platf with their flangesdisposed in\vardly,`cro`ss `frame `members connecting said side frame members, 'Y

able platform comprising transverse slat memoperably connected supplemental endless belt setically..flanged guideways cooperatively lat the rear `of said` foldable platform, transverse opposed rollers in` said body frame, one of said rollers being kadjustable and-resiliently held with re,` Y ,v I'

- with their flanges disposed inwardly, cross frame members connecting said side frame membersy' vertically hanged longitudinal `guideways on top of said -channeled side frame members, a foldable 1 platform comprisingl transverse slat members inovably supported at their ends normally on said flanged guideways, said `platform `slatmembers f in the movement and folding of said platform zontal article supporting base portionL slidably supported on said longitudinal verticallyiianged guideways cooperatively at the rear of said fold-` Aable platform, transverse opposed rollers in said body frame, Iendless-belt elements on said rollers, portions of said endless belt elements being se-'- formuslat members and said pusher element, and` van operably connected supplemental endless belt secured tosaidpusher element, said last named,` endless belt from said pusher element being extended across the tops of said platform slat members and aroundand under said rollers. 8-` The herein described rollingshelf structure, comprising arectangular body frame, said frame"l including vchanneled vlongitudinal side members vertically flanged longitudinal guideways on top of said channeled side fram'e members, a foldbers movably supported at their ends on said `1 25 flanged guideways, said platform slat members' in the movement andfolding of said, platform being slidably supported on the lower iianges of said ychanneled side frame members, apusher elef' ment slidably supported on said longitudinal vertically-flanged guidewaysat the rear of said foldy f1 ableplatform,transverse opposed rollers in said body frame, endless beltelements'on saidrollers,` portions of said endless belt elements being lsed cured to the under sides of said `transverseplat'- 135` form slat members and said pusher` element, ad` justable means acting upon said rollers for taut-` ening said endless belt elements and exerting a. yieldable tension in the tautening action, andan cured to said pusher element, said last mentioned` endless beltl .fromsaid pusher elementbeing'ex-` d 'K tended across thetops of said platform Slat members and around and under said rollers.

FLOYD 1J. PoWELng "145` f i being movable to and slidably supported on` the lo'vveriianges Vof said channeled side frame members, a separatepusher elementhaving ahori- 

